Gasifying burner



2 sheets-'shea 1 C. B. HOLM GASIFYING BURNER Filed Jan. 29, 1938 Jan. 6, 1942.

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Y In Sweden January 3 0, 1937 y 7 Claims.

The present invention relates to gasiiying burners and in particular to gasifying burners for small furnaces or ovens, such as portable ovens, in which liquid fuel is used as a combustible.

It is one of the objects of my invention to provide automatically operating means for opening and closing the valve device which controls the supply of liquid fuel to the vaporizer.

Another object of my invention is ,so to construct the vaporizer and so to arrange it relatively to the burner chamber that under all conditions the proper quantity of heat for` the gasification cf the fuel will be transmitted from the burner chamber to the vaporizer.

A further object of my invention is to provide a measuring device for delivering the exactquantity of starting fuel for heating and gasifying the cold fuel.

A still further object of my invention is to provide means for eiectively cleansing the fuel noz- Zle of the burner.

I attain these and further objects and advantages by Vmechanism illustrated in the accompanying drawings, in Which- Fig. 1 is a plan view of an apparatus yconstructed in accordance with my invention, part of the cover being broken away;

Fig. 2 is a vertical section on the broken line II-II of Fig. l;

Fig. 3 is a vertical section on the broken line III-III of Fig. l2;

Fig. 4 is a vertical section on the line IV-IV of Fig. l;

Fig. 5 is a vertical central section on an larged scale through the control valve;

Fig. 6 shows to a larger scale a section of a detail of the fuel valve operating device; and

Fig. 7 shows to a larger scale a section vof the fuel nozzle device.

Referring rst to Figs. 1 and 2, reference numeral I'U designates the casing of a portable oven orheating apparatus having an opening Il on its upper side. I2 is a reservoir for liquid fuel, such as petroleum, said reservoir being supported by the rear wall of the casing by means `of a bracket i3. Through an opening normally closed by a cover I4 the reservoir `can be filled with petroleum. A pump l5 the piston I6 of which can be reciprocated from the outside of the casing by means of a handle il secured to thepiston rod i8 is provided for producing a super-atmospheric air pressure in the petroleum reservoir, said pressure being indicated by a pressure gauge 19. A conduit connects the reservoir I2 with a control valve 2|, the construction and mode of operation of which will be described later on with reference to Fig. 5. By means of a conduit 22 the control valve 2l is connected to thelower portion of a vaporizer 23. IueI-gasied in Vsaid (Cl. 15S-42.1)

vaporizer is discharged' through a controllable nozzle device 24 opposite which there. is arranged a mixing chamber r25 forming part of` a 'burner chamber generally denoted at 28. g

For the purpose of Hstarting the vapoi'izer `I provide a starting burner cup `2'! .arranged to receive starting fuel, such as alcohol, from 'a measuring device 28 which per se forms nopart of the present invention through conduits 29 and 3.0. l'Ihe`measuring device communicates withran alcohol reservoir 3l which is secured'to'the rear wall ofthe casing YIl) by means of a bracket 32. Through an opening normally closed b y a Acover 33 having an `air inlet passage `33d the reservoir 3| can be filled with alcohol. By meansofja conduit 34, a shut-off valve 35 and a Aconduit 36 the measuring device 28 can be kbrought into communication with the air space of the fuel reservoir l2. v Having now described the general arrangement of Vdiiferent parts of .my improved gasifyingzburner, I will now proceed with a more'detailed Adescription of several parts and theirmode of oper,- v

ation. y n A,

Referring to Fig. v5, the control'valve '2Linserted between the conduits 21) and 22 Lisvenclosed in a valve box 31 which has securedtheretoI a cover '38. In the lower portionof the 'valvebox there is provided a resilient diaphragm 39 which dividesV the valve box into two chambersr 48`and,

4I.' Thel diaphragm has an opening through which extends a tube 42 yrigidly connected to the vdiaphragm as at 43. 'A secondresilientfdia'- phragm 44 has secured vthereto'a"hanged""body 45 towhich is screwed afmember 46 having an opening 41 through whichl the' tube 42 extends into a space 48 andl normally abuts with its upper end against the upperwall ofthe said space. vided in the upper portion of Athe ,tube 42,"a'nd 58 indicates a ring fixed on'the tubeportion located within the spacellii. A i

Adjustably secured to theflower' portion'of'the valve box 3l is a flanged member 5I'v whichforms. a valve disk arranged to cooperate with the lower end of the tube 42. A helical spring 52 inserted between the diaphragm'39 and the' member r'5l' tends to force the diaphragm and thus also' the tube 42 in an upward direction. "-Ahelical vspring 53 inserted `between the cover ofthe valve box and the body' 45 tends to move the saidbody and the tube 42 in a-.downvvard direction. The cover of .the valve box has aninwardly extending sleeve portion `82 f-having a `flangeA 54.'.y against. which rests a ring member 5,5-under the influence of a strong helical spring 56'i-nserted betweenthe cover of .the rvalve box andthe ring member. In the position shownA in the drawings'the ring member also abuts against the flanged portion .51 of the body 45. -Arod' 58 threadedinto @the 49 denotes" small radial .apertures pro- Y `ing button 91.

40, Whereas the conduit 22 communicates with the chamber 4 I of which the one |09 has substantially the same As will be seen from Fig. 4, the vaporizer 23 is formed by a receptacle having an upper enlarged portion 10 and a lower portion-1| of smaller cross-sectional area, which is connected with the 'Y hollow cross piece 11 forming a mixing chamber together .with an inlet portion 18 which is 1ocated opposite the fuel nozzle device and is adjustably mounted in a pipe 19. 'Ihe shank portions are of rectangular cross section and have yajnumber of apertures 80 for the flame in their upper Walls. In their inner side walls the shank portions are further provided with a number of apertures 8| which serve to supply heat to a plate'82 consisting of' heat-conveying material and arranged in spaced relation between the lshank portions of the burner chamber and the upper portion of the vaporizer and connected to the lower portion of the vaporizer at a level 83.

The fuel valve for controlling the amount of gasied fuel flowing through the nozzle device is indicated at 84 in Fig. 7. The stem 85 of the fuel` valve is enclosed,at a portion of its length, vby a pipe 86 which has an opening 81 for the ad-V mission of gasied fuel linto the nozzle chamber 88. The pipe 86 is carried by an angle 89 secured to the casing I0 and by a member 90 forming a part 0f the fuel nozzle device. The outer end of the valve stem 85 is connected by means diameter as the larger opening |05, while the needle I0 has substantially the same diameter as the smaller opening |06.

When the valve stem 85 is retracted, the smaller opening |06 is rst made free, while the larger opening is still closed. Upon continued retraction of the valve stem, the larger opening |05 is also made free. Since the needles |09 and II 0 have substantially the same diameters as the respective nozzle openings,an effective cleansing from coked fuel is obtained, which is not the case in arrangements where the cleansing needle'v is conical and serves to regulate the sizeof the flame.

The apparatus described operatesin the following manner.

At the startingv of the burner the vaporizer is lled with petroleum to the level indicated at IIB in Fig. 4, and the petroleum reservoir I2 is under a pressure of for instance 15 lb. per sq. in. above atmospheric pressure, said pressure being set up by means of the pump I5. To start the burner, the valve is opened, so Athat compressed air from the petroleum reservoir will pass through a conduit 36, the valve 35 and the conduit 34 yinto the measuring device 28 and will thereby force a certain quantity of alcohol of a right-handed thread portion 9| to a screw 92 having left-handedthreads. The screw 92 is threaded into a nut 93 secured to the front Wall L94 of the casingv I0. The screw 92 has an elongation 95 in the form of a rectangularly shaped pin which engages a sleeve 96 secured to a turn- Between the front wall 94 and a projection 98 secured to the sleeve V96 there are `arranged abutments 99 and |00 to limit theturn- ,ing movement of the button 91 within a range tionin the screw 92, but it will be prevented from turning movements due to the fact that the `threaded portions 9I and 92 are provided with right; and left-handed threads, respectively.

In order to prevent leakage of gasified fuel from the vaporizer, I provide al'bellows member lIIl3'secu1-ed'on the one hand to the tube 86 and on the other hand to the stem 85 and thus allow- .ing displacement of the stem in the longitudinal direction and yet'forming a gas-tight connection `between the valve stem and the interior of the vapr'Zer-- x 1 The nozzle device i'sprovided with two openthrough the conduits 29 and 30 into the starting burner cup 21.

At its flow from the conduit 29 to the conduit 30 the starting fuel can be lit through an opening II8 provided in the front wall of the casing I0. The combustion of the starting fuel takes place in the starting burner cup 21, combustion air being supplied to the cup through passages I9 and |20. Thereupon the fuel valve is opened by turning the button 91. By the heatr transferred from the flame of the starting fuel to the upper portion of the vaporizer the fuel contained therein is caused to boil and escapes in agasiiied state through one or both of the nozzle openings, is mixed with air in the mixing chamber 25, and is ignited by the heat produced by the starting burner. The burner chamber gives off heat partly through the apertures 80 on the upper side of the shank portions 13 `and 14 and partly through the apertures 8| Ain the inner's-idefwalls of the shank portions. By'the heat transferred from the apertures 8| to the heat-conveying plate 82 and the vaporizer the fuel in thegas producer is kept boiling, and the pressure prevailing in the same will be increased and, as a consequence thereof, the fuel level will be depressed to the level indicated by the dotted line ,83, At the same time, the pressure also rises in the conduit 22 and thereby moves the diaphragm 39 and the tube 42 upwards to the position shown in Fig. 5. The valve formed by the lower mouth of the tube 42 and the valve disk 5| will thus be opened, and fuel will be forced from the reservoir I2 through the conduit 20, the valve chamber 40, the opening 41, the space 48, the small aperturesS, the tube 42, the chamber 4I andlthevconduit 22 into the lower portion 1I of the vaporizer. The quantity of fuel supplied to the gas .producer corresponds substantially to the quantity gasied in the vaporizer so that the fuel contained in thelower maintained at thek level indicated atx83.

The gasification of fuel in the vaporizer must be effected so rapidly by the flame of the starting burner, that the pressure kin the vaporizer rises to such an extent that the diaphragm 39 can be lifted against the action of the pressure prevailing in the petroleum reservoir and the conduit-20 and the valve chamber 40. The vaporizer must consequently be shaped in such a manner, that the ,heat developed -by the starting burner can begeasily taken up by the fuel. To this end, the upper portion 'I0 of the vaporizer, which at the starting of the burner contains fuel, has a comparatively large horizontal cross section so that the fuel contained in the said portion forms a comparatively thin layer having greatdimensions in the horizontal direction.

For a reason to be explained later on the lower portion of the vaporizer should not be heated to ahighdegree. Y`To this end a screen |2| is arranged between the starting burner cup and the lower portion of the vaporizer so as to prevent as far as possible transmission Vof heat from the starting burner ame to the said portion. Another screen |22 prevents the starting burner flame from contacting the'fuel nozzle device 24.

If. for some reason or other, for instance, when using the burner at the first time or if the burner was out of operation for a long period, no or too little petroleum is contained in the vaporizer, the control valve can be opened manually by means of the level 60 which extends a short distance outk of the casing I0. By lifting the lever 60 the body 45 is moved upwards against the resistance of the spring 56 and thereby the ring 50 is also moved upwards by the body 45 so that the tube 42 will be removed'from the valve disk 5| and petroleum can iiow from the reservoir I2 into the vaporizer. The spring 56 offers a comparatively great resistance to the actuation of the lever `6i), in order to render difficult the lifting of the lever and thus to prevent manual opening of the valve by mistake.

Under normal working conditions heat is supplied tothe vaporizer from the apertures 8| of the burner chamber by means of the heat-conveying plate 82 which is in direct contact with the lower portion of the vaporizer ati the normal fuel level 83 so that the greatest portion of the heat is transmitted to the place where the boiling of the fuel takes place. A certain portion of the heat is transmitted to the upper portion of the vaporizer-by radiation from the plate82. In order to prevent oscillations of the fuel-level during the operation of the burner, the lower portion of the vaporizer should not be too narrow.

By providing two diaphragms 39 and 44 in the control valve the position of the tube 42 relative to the valve disk 5| will not be materially influenced by variations in the pressure prevailing inthe petroleum reservoir |2. If this pressure should be decreased to a small extent, both diaphragms will tend to move towards each other. The upward movement of the diaphragm 39 is, however, compensated for by. the downward movement of the tube 42, said downward movement being effected on account of the contact between the upper endv of the tube and the upper wall of the space 48.

Should, however, the pressure in the petroleum reservoir be decreasedbelow a certain minimum value, the body 45 on account of the pressure reduction in the chamber 40 and under the iniiuence of the spring 53 will bring the tube 42 into contact with the valve disk and thereby shut ol the supply of petroleum to the vaporizer.

When the .burner is to be put .out ofy actionthe' fuelY valve l84 issclosed Aby, turning .the button :91. Theflame is extinguished, and the heat supply from the burner chamber to the .vaporizer ceases. Assuming that the pressure prevailing in the petroleum reservoir and the vaporizer. is V15 1b. per sq. in. above theatmospheric pressure, and that the temperature of the vaporizer is about 50 F. higher than the temperatureof thefsaturated fuel vapour at the above-named pressure, then at the extinction of the burner flame the pressure in ther vaporizer will Yrapidly rise by .a few pounds per square inch, but will soon be decreased to the first-named value. However,r since the-vaporizer at the same time is cooled,v the pressure will be maintained substantially constant until the temperature of the vaporizer has been decreased to or substantially to the temperature of the saturated vapour at a pressure of 15 lb. per sq. in. above atmospheric pressure. Thereupon, the pressure begins to fall and fuel will flow from the fuel'reservoir into the vaporizer. The temperature of the vaporizer will be lowered by the fuel supplied, and the pressure will thus continueto fall in spite of the reduction in volume caused by the fuel flowing to the vaporizer.

Whenthe pressure in the vaporizer hasbeen reduced to a certain value, for instance 12 lb. per sq. in., the diaphragmg of the control valve 2| will be moved downwards so as to shut off the connection between the interior of the tube 42 and the valve chamber 4| The supply of petroleum to the vaporizer is then entirely interrupted. The vquantity of petroleum supplied tothe vaporizer during the period from the reduction of the pressure in the lvaporizer to the closing of the control valve is such that the fuel in the vaporizer will be raised to the level indicated by H6, which issuitable for starting the burner anew by means of the starting fuel.

The slower'thepetroleum flowsA to the vaporizer during the above-named period the longer is the time allowed for the cooling of the vaporizer, which cooling is effected by radiation and conveying of heat and, to a lower degree, by the cold petroleum supplied to the vaporizer. In order to render possible a reduction of the pressure during the comparatively long period for cooling the vaporizer, I provide a restricted flow of the petroleum by means of the small apertures 49 through which the petroleum must flow on its way from the petroleum reservoir to the vaporizer. Were it not for this restricted flow, the pressure in the vaporizer could not be decreased to the value required for closing the control valve.

It is thus of importance for the reliable operation of the controlling device,that the flow to the vaporizer of petroleum is throttled and that the upper portion of the vaporizer is so large as compared with the supplied quantity of potro;- leum that the vaporizer is cooled so rapidly during the supply of petroleum, that thev pressure will be reduced in spite ofthe reduction of the gas space of the vaporizer during such supply. Besides, the vaporizer should be so formed that at a new starting of the burnery theiiame of the starting fuel readily can heat and gasify the fuel in the vaporizer. This is effected by giving the vaporizer the shape shown in the drawings so that the fuel at the closing of the control valve is raised to the level indicated at H6 in a portion of the vaporizer which can be directly heated by the flame of the `starting fuel. Further, yto shorten the period between the extinction of the burnerfiame andthe closing of the control'valve, the mass of Vthevapn'iriz'er should be small as compared with the cross-sectional area of its upper portion so as to renderV possible a great radiation and convection of hea-t from the vaporizer to the surrounding atmosphere. It is therefore suitable to construct the vaporizer with walls as thin as is possible with regardi to the required strength of the walls.

As will appear from the foregoing description, the opening as well as the closing of the control valve device 2| is solely effected in response to variations in the pressure prevailing in the vaporizer and fuel reservoir. Further the arrangement vis such that at the moment when the control valve is closed the fuel in the vaporizer attains a level suitable for starting the burner anew. Such an operation is not attainable with means for closing the control valve mechanically,

for instance simultaneously with the closing of v a burner chamber arranged to receive gasied c fuel from said vaporizer and tol receive combustion air, a fuel reservoir, a conduit for connecting said vaporizer to said fuel reservoir, a control valve in said conduit, and means responsive to a-certain rate of reduction of pressure in said vaporizer for closing said control valve.

Cil

2. A gasifying burner comprising a vaporizer,

a burner chamber arranged to receive gasified fuel from said vaporizer and to receive combustion air, a fuel reservoir, a conduit for connecting said vaporizer to said fuel reservoir, a control valve in said conduit, and means responsive to Variations in the pressure prevailing in said vaporizer for opening said control valve upon increase of said pressure above a predetermined value and responsive to a certain rate of air pressure in said vaporizer for closing said control valve.

3. A gasifying burner comprising a vaporizer,

a burner chamber arranged to receive gasied e fuel from said vaporizer and to receive combustion air, a fuel reservoir, a control valve including a valve box, a resilient diaphragm dividing said valve box into a first and a second chamber, a valve secured to said valve box in said second chamber, a tubular member connected to said diaphragm and forming a valve seat for said valve and extending into both of said chambers, said tubular member having apertures for restricted ow of liquid fuel from said iirst chamber into said tubular member,` resilient means tending to force said diaphragm toward said first chamber, a conduit for connecting said first chamber with said fuel reservoir, and a conduit for connecting said second chamber With said vaporizer whereby at a predetermined rate of reduction of pressure in the vaporizer the control valve will be closed.

4. A gasifying burner comprising a vaporizer, a burner chamber arranged to receive gasified fuel from said vaporizer and toreceive combustion air, a fuel reservoir, a control valve'including a valve box, a rst resilient diaphragm dividing said valve box into a firstand a second chamber, a valve secured to said valve box in said second chamber, a tubular member connected to said diaphragm and forming a valve seat for said valve and extending into both of said chambers, said tubular member having apertures forl ren f uu stricted now-of liquid fuel from said rst chamber into vsaidtubular member,.resi1ient means tending to force said diaphragm toward saidfirst chamber, a second resilientdiaphragm disposed in said first chamber, resilient means tending to force saidv seconddiaphragm toward said rst diaphragm, a conduit for connecting said first chamber with said fuel reservoir, and a conduit for connecting said second chamber with said vaporizer whereby at a predetermined rate of reduction of pressure in the vaporizer the control valve will be closed.' A.

. 5. A gasifying burner comprising a vaporizer, a burner chamber arranged-.to receive gasified fuel from said vaporizer andto receive combustion air, a fuel reservoir, a control valve including a valve box, a first resilient diaphragm dividing said valve box into arst anda second chamber, a valve secured to saidvalve box in said second chamber, a Vtubularmember connected to said diaphragm and .forming a valve seat for said valve and extending into both of said chambers, said tubular` member having apertures for restricted flow of liquid fuel fromsaid first chamber into said tubular member, resilient means tending to force said diaphragm toward said rst chamber, a second resilient diaphragm `disposed in said first chamber, resilient means tending to force said second diaphragm toward said irst diaphragm, a manually operable device for moving said tubular member from said valve, a conduit for connecting said first chamber with said fuel reservoir, and a conduit'for connecting said second, chamber with said vaporizer whereby at a predetermined rate of reduction of pressure inthe vaporizer the kcontrol valve will be closed.

6. A gasifying `burner comprising a vaporizer, a burner chamber arranged to receive gasifled fuel from said vaporizer and `to receive combustion air, a fuel reservoir, a control valve including a valve box, a first resilient diaphragm dividing said valve box intora first and a second chamber, a valve secured to said Valve box in said second chamber, a tubular member connected to said diaphragm and forming a valve seat for said valve and extending intoy both of said chambers, said tubular member having apertures for restricted now of liquid fuel from said rst chamber into said tubular member, resilient means tending to force said diaphragm toward said first chamber, a second resilient diaphragm disposed in said rst-chamber, resilient means tending to force said second diaphragm toward said first diaphragm, a manually operable device for moving said tubular member from said valve, resilient lmeans arranged to render difficult the operation of said device, a conduit for connecting said first chamber with said fuel reservoir, and a conduit for connecting said second chamber with said vaporizer whereby at a predetermined rate of reduction of pressure in the va-v porizer thevcontrol valve will be closed. I

k'7. In a gasifying burner including a vaporizer, a fuel reservoir, and a conduit for connecting said vaporizerto said fuel. reservoir, a control valve in said conduit, said control valve including a valve box, a resilient diaphragm dividing said box into two compartments, a valve body and seat structure in one of said compartments, andmeans independent .of said valve body and seat structure to provide for lrestricted flow of fuel between said compartments. 4

, CARL BERNHARD HOLM. g 

